APOE and systemic sclerosis: CCL19/APOE has been identified as a major fibroblast subcluster in scRNA seq of SSc skin appearing mainly adjacent to vascular structures [9], with additional studies validating CCL19 expression in the skin of diffuse cutaneous SSc (dcSSc) patients using quantitative PCR analysis, finding its expression correlated with markers of vascular inflammation and macrophage recruitment [52].